One more day like this, and Paula Creamer will no longer be the best LPGA Tour golfer who hasn't won a major.

Creamer kept her game together as a dozen others were losing theirs on a grueling day at the U.S. Women's Open on Saturday, taking a three-shot lead over Wendy Ward that she hopes will hold up in the final round.

That, and her left thumb.

Creamer, who has eight top-10 finishes in majors at age 23 but has yet to win one, is playing in only her fourth tournament since sitting out four months to surgically repair a hyperextended joint. The injury is so painful she limits her practice shots because she can't stand the constant pounding of her golf club striking the ground.

"I'll probably sleep with an ice bag on," Creamer said. "I'm afraid to take the tape off -- my thumb is going to explode out of it. But the more I think about making pars, the less the thumb bothers me."

Maybe that was the best way to prepare for the demanding Oakmont Country Club, whose stray shot-grabbing bunkers and tricky-to-read greens doomed the hopes of contender after contender on a day when play began at dawn and extended to sundown. Namely, stay off it as much as possible.

Creamer, who played 29 holes Saturday, is 1 under for the tournament with five holes remaining in a third round that will be completed Sunday morning. The 37-year-old Ward, a four-time LPGA Tour winner, has only No. 18 to play. Suzann Pettersen is four back with four holes to go, while 15-year-old Alexis Thompson, Amy Yang and Brittany Lang are five back. Only Thompson completed the third round.

"You know, this was a tough day," Creamer said. "I got here at 5:30 this morning and it's 9 now. That's a lot of golf. On this course, I mean, 18 holes is enough."

Creamer, sixth in the last two U.S. Women's Opens, played all but two holes of her 1-under 70 in the morning -- the only below-par score among those completing the second round on Saturday. She followed that by getting three birdies and two bogeys during the third round, with the second bogey coming on No. 13 just as the USGA sounded a horn halting play due to dwindling light.

"I played really consistent -- I stuck to my game plan," Creamer said. "If I hit a lot of greens, I know birdies will come. I know every par I won't lose ground, so I keep going with that mindset. I was trying to stay at patient as I can."

All this only a weekend after she missed the cut in the Jamie Farr Classic.

The only other 70 of the day was by Thompson, who is playing in her fourth Women's Open -- her fourth! -- despite not yet being 16 but only her second tournament as a pro. She is at 4-over 217.

Like most teenagers, Thompson is glad she gets to sleep in Sunday.

"I'm really thankful I don't have to come back at 7:30 to play for likely just a hole," said Thompson, whose father, Scott, is toting her bag.

"I never thought of that; I'm just watching their games and how good they are," she said. "How good they putt is amazing."

Imagine the quandary the LPGA Tour would find itself in if Thompson would somehow win; she's not eligible to play full-time on the tour until she's 18.

Of course, maybe Creamer has this going for her: Of the last 14 majors, 11 have been one by first-timers.

As Creamer was stringing together par after par, playing partner Cristie Kerr -- the runaway 12-shot winner of the LPGA Championship only two weeks ago -- was faltering.

Kerr went from one shot off the lead at the start of the third round to eight down in 12 holes, aided by back-to-back double bogeys on Nos. 4 and 5. She birdied both holes during the first two rounds.

At the same time, Creamer birdied the fourth and parred the fifth, quickly separating herself from pre-tournament favorite Kerr by six shots.

It was the exact opposite of last year's Women's Open third round when, also playing together at Saucon Valley, Kerr had a 1-over 72 and Creamer soared to a 79. Kerr ended up tying for third while Creamer had a final-round 69 to tie for sixth.

So much for rest being a factor. While Creamer played the equivalent of a full round and much of another, Kerr played only 13 holes because she completed the second round before heavy rain halted play Friday.

Creamer has won eight LPGA tournaments but doesn't have a victory since 2008. Her best finishes in majors were third-place ties at the 2005 LPGA Championship and 2009 Women's British Open.

Creamer tied for 42nd at the LPGA Championship but was at another major this year, too; bored during her layoff following surgery, she attended the Masters.

If the leaderboard holds up, an American will win the nation's Open championship for only the second time in six years; Creamer and Ward are from the United States. Only two Americans are currently ranked in the world top 10: No. 1 Kerr and No. 10 Michelle Wie, who missed the cut.